12" woofer with ff85k

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I want to build some speakers w/ parts I've got, and need woofers to pair w/ ff85k's (older ones). I think this is what people are calling "fast" speakers, but I don't want the woofer to be powered.
I've got some old 3 way cabinets w/ very cheap woofers, and want to replace them. (all the other drivers in the cabinets are broken/not being used) I'm thinking I could use the 85k's as the mids & highs, cross over at 350ish hz probably first order.
I've read threads that are very similar to what I want to do, full of driver recommendations, but all are for smaller 6-8inch drivers for the lows. Can anyone recommend 12" woofers, or at least point me in the correct direction as to what parameters I should be looking for? I'll be completely honest, some day I want to build the perfect speakers, but don't have a lot of time for research right now. I threw these together today w/ the very cheap woofers that are in the cabinets w.out a crossover, and they sound surprisingly good. I think I can get something pretty well together w/out a ton of effort.
Cabinets are 11x15x27 w/ a front port.

I realize this is the sort of broad question that doesn't always get answered, but it's worth a try :) Thanks for any help.
maybe I should mention, the amps are 70ish watt push pull tubes.
 
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frugal-phile™
Joined 2001
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Given that i have a number of vintage Foster 12" that suit the task that is what i would use personally. They were XOed to a Foster 38mm dome at ~3.5k so they have the extension i like at the top, and we have used the same as woofers for a sub for a client.

If i had to look to something new, i'd look for similar.

I even have a sketch for a FAST with these woofers.

dave
 
Hi,

The point with a FAST is not to chuck shedloads of money at the bass
unit compared to the mid treble, and with a passive x/o (first order
series is the place to start), the important thing as well as a decent
bass alignment is a higher senstivity for BSC so you don't need to
L-pad the mid treble that much (if at all).

The world of 12" drivers is a murky one at the budget end, but the
point of the bass unit in a FAST is to improve the FR driver, not be
the point of the design.

You've got about 2 cuft and want a driver about 92dB,
a few dB, say 3 to 4 above the FR to be mated with.

MCM Electronics: Home and Pro Audio/Video, Security and Test Equipment
Probably has the best choice of budget 12" drivers.

rgds, sreten.
 
Given that i have a number of vintage Foster 12" that suit the task that is what i would use personally. They were XOed to a Foster 38mm dome at ~3.5k so they have the extension i like at the top, and we have used the same as woofers for a sub for a client.

If i had to look to something new, i'd look for similar.

I even have a sketch for a FAST with these woofers.

dave

What's the loading for the Foster 12" in your FAST?

Here's what my pair ended-up like, now in heavily stuffed 50L boxes in a friend's basement.

An externally hosted image should be here but it was not working when we last tested it.


IG
 
Thanks everyone. My budget isn't super tight.. I can spend up to about $200 a piece for them.. I'm not out to waste money, either or go all top of the line just for the sake of it. I've got some money to use at Madisound, so have been looking at their woofers, but I don't need to purchase from them.. (they don't have the alphas)

I always see the eminence Alpha's recommended. Why not the Beta's or Delta's? They look like better models, but I have a lot to learn about speakers and right now I don't understand many of the parameters.
I've got a lot of reading to do. Maybe a quick and simple DIY is an impossible task :),
 
frugal-phile™
Joined 2001
Paid Member
...Madisound, (they don't have the alphas)

They can get any Eminence by special order -- i got my alphas from them.

eminence Alpha's recommended. Why not the Beta's or Delta's?

The Q on the alphas is suitable for OB. I'd personally not consider them anywhere else.

Have you looked to see if Acoustic Elegance (nee Stryke, Llambda) have anything interesting in your budget.

dave
 
I was looking for something similar a few days ago but I remember than none of the 12" woofers I could find could excite me enough to go that route. That's why I had decided to go with an 8"woofer or a 10" at max.
I checked again and the only one that looked at least descent in that price range was the ESS 689-1220 which looks like a quality build and WinISD reports a Qtc of 0.9 in your enclosure sealed with a 40Hz f3. It has 91.5db sensitivity but it is 4ohms so make sure your amp can handle it nicely (that could be a problem with tubes).
Since your box is ported perhaps some light port stuffing will turn it to a sort of aperiodic box and lower the Qtc a bit. (just a wild guess I could be wrong)
 
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Not sure if it is a really good idea, vut the fostex ff225wk seems interesting. It will have similar looks and some tonality resemblce. I also offers decent bass (i heard it) and is so widerange that you could try many crossover points.

There are many good options for a 8"-10" midbass. I don't think the FF225 is an optimal choice though.
Having said that perhaps a 10" (easy to fit with an adapter baffle) would be a better choice than a 12" at that price range.
 
Ex-Moderator R.I.P.
Joined 2005
I supppose you first and most need a woofer with appropriate SPL to match your fullrange driver, and with enough 'headroom' to do the BSC thing
and not forget it should ofcourse have decent bass

I would be tempted to try the 'famous' Seas Prestice A26RE4
 
I supppose you first and most need a woofer with appropriate SPL to match your fullrange driver, and with enough 'headroom' to do the BSC thing
and not forget it should ofcourse have decent bass

My understanding is that one needs a midbass with higher sensitivity than the full range driver so there is no need for BSC circuit.
My guesstimate was around 3db (or more) higher at the midbass frequencies (not the stated SPL which could be at higher frequencies) but that like I already said is just a guesstimate.
Do you (or anyone else) know what sensitivity one should look for to match the ff85wk without the need for a BSC circuit?
 
Ex-Moderator R.I.P.
Joined 2005
depends
if your woofer have very good low bass, you might get away with less BSC
also consider that the little Fostex fullrange may not be for playing very loud
so you need a woofer that 'comes alive' at moderate SPL, but may not need the higher SPL 'control'
 
Thanks everyone again.. all the conversation is helping fill in the blanks in my speaker knowledge.
I have noticed all the affordable "woofers" are wide range PA speakers. Maybe I should increase my budget to 300 per driver.. then plan on getting nice true woofer drivers that I re-use in a different cabinet some day.
The adapter and 10" isn't a bad idea either.. but opens up too many new options :).

Any parameters I should be focusing on, other than the db/w/m and frequency? I guess my build isn't anything too unique or specific.. Nice sized box, can leave the port or seal it, don't need a huge frequency range, etc.....

Tinitus makes a good point, in that most of the listening will be moderate SPL.. It'll get loud occasionally, but those will be times I'm not critical of sound quality.

Ok, one real question.... Am I on the right track with wanting to stick to a simple first order filter? I realize the inductor for the woofer will be large and expensive. I'm coming from a low wattage SET background (as far as my hi-fi experience) so still always have the idea of a very simple signal path in mind.

Someone mentioned 4 ohm drivers, and my transformer does have 4 ohm taps. But then I'm confused about the final impedence of the whole speaker.. that isn't going to be an even 4, 8, or 16. (yep.. more reading to do)
 
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The Q on the alphas is suitable for OB. I'd personally not consider them anywhere else.

I just had a closer look, wow, ya, that thing doesn't quite work thanks for catching that. I've used the 8" and figured it would be along the same lines.

Anyways, given what you've now said about budget and such, how about this guy: The Madisound Speaker Store

Stuff the cabinet well and it'll be pretty much a sealed box, but lots of extention. About the right sensitivity match.
 
Oh and, you could do a 1st order cross over. I have my reasons for using second order, but a lot of people do first order. A second order will have better phase tracking, suppress woofer break up better, reduce excursion on the full range better, less driver interference in the high frequencies. But the first order is cheaper, easier, and less phase rotation. There may be other pros and cons, I'm just thinking off the top of my head.
 
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